CyclingNZ Home

Notice: Use of undefined constant person - assumed 'person' (this will throw an Error in a future version of PHP) in called from on line in /home/cycling/public_html/cnz5_connect.php on line 57
Power!
Date: 17 Mar, 2005
Contact: Kinetic Edge - Training Technology

Gone are the days when to become good at cycling you just rode your bike.  Now we have cycle computers, heart rate monitors, GPS and power monitors to tell us to ride harder, slower or to give up and go home!  Apart from the immense amount of entertainment these toys provide they do actually have a purpose and that is to give you an indication of how hard you are working.

 

Twenty years ago cycling computers were the gadget to have, then heart rate monitors came along and now it's surprising to see a cyclist without one.  However, now we have power output that has actually been around for over a decade but hasn't become very well used until the last few years.  But what is power output?

 

Simply, power is energy per unit of time or the rate of doing work.  Power is measured in watts and producing one watt is equivalent to expending one joule of energy per second (or 0.01433 kilocalories per minute).  Accurate training program prescription relies on setting intensities for training efforts whether they are low, high or in between.  This can be done via heart rate, cycling speed, by a rating of perceived effort or by using power output.  Most people are familiar with heart rate or cycling speed, but less so with power output.  Using power output has several advantages over heart rate or cycling speed.  This is because it is a constant measure and does not rely on your internal physiology (heart rate) or environment (cycling speed).  As an example, when we become dehydrated we experience what is called cardiac drift.  Despite riding at the same cycling speed or power output our heart rate rises, therefore making heart rate training zones invalid.  However, power will tell you exactly what is happening no matter your hydration status or what the weather is like.  You can compare day to day training and racing week to week and so on.

 

As an example, there is some data from a rider who completed two Saturday morning Auckland Waterfront 16km time trials:

 

Ride

Time

Average Speed (kph)

Average Heart Rate (bpm)

Average Power Output (W)

1

23:30

39.6

171

312

2

22:02

42.4

158

312

 

Based on time and average speed you would instantly think they rode better in time trial two and that their training was working.  But in actual fact they sustained the same power output in each time trial so they have not improved.  The large difference in time came from improved body position, reducing drag, equipment aerodynamics and changes in weather.

 

A valid and reliable measure of power used to be available only in sports science laboratories, however over the last decade several power output monitors have become available.  It is extremely difficult to accurately quantify and measure power output therefore they are not cheap.  Each model has its advantages and disadvantages (eg. Some only use shimano components) so when looking to buy be aware of their constraints and compare this with what you are hoping to achieve instead of just looking at the price tag.

 

  1. Ergomo Sport Measures power through torque in the bottom bracket from one leg only.
  2. Polar Calculates power through a chain vibration sensor that measures chain tension.
  3. PowerTap Has a torque measuring hub in the rear wheel.
  4. SRM Measures torsion in the crank arms or essentially hom much push you are putting into the pedals.

 

The benefits of training with power are enormous as it drastically improves the specificity of your training, and this is why the professional cyclists are using it.

 

Amy Taylor is one of the founders of Kinetic Edge Training Technology (www.kecycling.com).  Amy is a Auckland based Exercise Physiologist with an MSc(Hons) in Sports Science.  She has been cycling for 14yrs and coaches recreational to world champion cyclists.

 

This article originally appeared in the December issue of Endurance Sport Magazine Issue 21.

 

Click to enlarge...

CONTINUE READING
Latest News
The Cycling Advocates Network (CAN) welcomes an increase in the driving age to 16, but says the government also needs to invest in professional cycle training to improve road safety. CAN spokesperson Anne FitzSimon says one of the best ways to raise driving standards is to make cycle training >>
This weekend I got my first taste of NRC racing in America. The Dana Point GP race on sunday was a 90min crit round a fast but very technical circuit in the streets of Dana Point, with a huge crowd and the top US teams present it was a pretty big event and had an awesome atmosphere. Bike Religion >>
Looking for a different challenge and some fun a West Coast couple riding a Unicycle are amongst the 1100 riders doing the Around Brunner Cycle event on the West Coast this Saturday. "We've been riding unicycles for around three years now," Alison Dixon from Blackball said. "It started off >>
Latest Articles
Former world Champion Hayden Godfrey is the latest big name to enter the Around Brunner elite road race this weekend. The 2008 Omnium World Champion was knocked off his bike in Christchurch in February, putting his arm through a car windscreen which required surgery meaning he missed valuable >>
This weekend is again a busy weekend for the Mico/All About Plumbing Cycling team presented by Revolution Racing. Saturday has the team lining up on the West Coast in Greymouth for the 130km National Point Series (NPS) Around Brunner Cycle Ride. Team director Steve Elden says "the ride or race for >>
Less than two weeks after entries opened, interest is already high in Cycling Southland's Harrex Group Corporate Pursuit being held in June. Organisers expect to easily fill the field of 32 corporate teams that will compete in New Zealand's only indoor velodrome in Invercargill in a grading >>
 Photo Gallery

Notice: Use of undefined constant pid - assumed 'pid' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57
Tour of Southland

Notice: Use of undefined constant pid - assumed 'pid' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57
Sam Brothers bioSPORT Crits

Notice: Use of undefined constant pid - assumed 'pid' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57
Waterfront TT 10 Oct '09

Notice: Use of undefined constant pid - assumed 'pid' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57

Notice: Use of undefined constant ptitle - assumed 'ptitle' (this will throw an Error in a future version of PHP) in display_page_bottom called from /home/cycling/public_html/cnz5_science.php on line 286 in /home/cycling/public_html/cnz5_connect.php on line 57
Waterfront TT 24 Oct '09
Home Kiwi Riders Sports Science Beginners Articles Riders Reports Tech Corner Contact
© Cyclingnz.com 2021 | Login | Design by OnfireDesign